This invention relates to a fish sauce for use as a seasoning or taste enhancer, in which no peculiar or undesirable odor is present. There are a number of fish sauces available, prepared from a variety of fish and shell fish, which are used as seasonings or taste enhancers. Among the more well-known are nuoc mam, nampla (nom pla) and patis, used in Southeast Asia; and Ishiri (derived from squid organs during the production of dried squid), Shottsuru (derived from stand fish, and others), and Ikanago (derived from sand eel) which are all used in Japan. Each of these seasonings has its own characteristic flavor (referred to as ‘umami’ in Japanese) and they are useful for enhancing the taste of foods or imparting a new taste to foods. Fish sauces have been drawing attention for their characteristic flavor and they are used in various foods. However, the use of fish sauces are limited to certain food groups, since in other food groups, any underlying undesirable odor existing in fish sauce tends to impair the taste of the food rather than enhance the taste or induce a new taste.
To overcome the problems of undesirable odors in fish sauces, various methods for their removal have been proposed. These include a method using ultrafiltration (Japanese Unexamined Patent Publication No. 346767/1992); a method in which the pH of the fish sauce is adjusted and the resulting sauce is subsequently subjected to steam distillation (Japanese Unexamined Patent Publication No. 64563/1993); and a method comprising adsorbing volatile amines to undecomposed products of koji (malted rice) (Japanese Unexamined Patent Publication No. 47051/1991). However, each of these methods is subject to problems. The ultra-filtration method, while being useful for removing certain undesirable odor components, is not able to remove all of the undesirable odor components liable to produce unpleasant, fermentation and briny odors, and there is a tendency to also remove palatable odor components along with those which are not desirable. In the method comprising adjusting the pH of a fish sauce and subsequently subjecting it to steam distillation, whereby undesirable odor components tend to remain in the sauce; and, in particular, it is not possible to remove briny and fermentation odor components using the said method. Also, in using the method whereby volatile amines are adsorbed by undecomposed products of koji, an undesirable koji-type odor is imparted to the sauce, and it is also not possible to remove fully those substances which give rise to undesirable odors, other than amines.